Change the way nuked users' posts are handled. Allow null in the user_id column of posts. Show these posts in the posts stream.

app/serializers/basic_post_serializer.rb

@@ -8,15 +8,15 @@ class BasicPostSerializer < ApplicationSerializer
              :cooked
 
   def name
-    object.user.name
+    object.user.try(:name)
   end
 
   def username
-    object.user.username
+    object.user.try(:username)
   end
 
   def avatar_template
-    object.user.avatar_template
+    object.user.try(:avatar_template)
   end
 
   def cooked

app/serializers/post_serializer.rb

@@ -46,11 +46,11 @@ class PostSerializer < BasicPostSerializer
 
 
   def moderator?
-    object.user.moderator?
+    object.user.try(:moderator?) || false
   end
 
   def staff?
-    object.user.staff?
+    object.user.try(:staff?) || false
   end
 
   def yours
@@ -70,7 +70,7 @@ class PostSerializer < BasicPostSerializer
   end
 
   def display_username
-    object.user.name
+    object.user.try(:name)
   end
 
   def link_counts
@@ -101,11 +101,11 @@ class PostSerializer < BasicPostSerializer
   end
 
   def user_title
-    object.user.title
+    object.user.try(:title)
   end
 
   def trust_level
-    object.user.trust_level
+    object.user.try(:trust_level)
   end
 
   def reply_to_user

app/serializers/post_stream_serializer_mixin.rb

@@ -15,15 +15,13 @@ module PostStreamSerializerMixin
     @highest_number_in_posts = 0
     if object.posts.present?
       object.posts.each_with_index do |p, idx|
-        if p.user
-          @highest_number_in_posts = p.post_number if p.post_number > @highest_number_in_posts
-          ps = PostSerializer.new(p, scope: scope, root: false)
-          ps.topic_slug = object.topic.slug
-          ps.topic_view = object
-          p.topic = object.topic
+        @highest_number_in_posts = p.post_number if p.post_number > @highest_number_in_posts
+        ps = PostSerializer.new(p, scope: scope, root: false)
+        ps.topic_slug = object.topic.slug
+        ps.topic_view = object
+        p.topic = object.topic
 
-          @posts << ps.as_json
-        end
+        @posts << ps.as_json
       end
     end
     @posts